Barons’ War, (1264–67), in English history, the civil war caused by baronial opposition to the costly and inept policies of Henry III. The barons in 1258 had attempted to achieve reform by forcing Henry to abide by the Provisions of Oxford (seeOxford, Provisions of). When, by the Mise of Amiens (1264), the Provisions of Oxford were declared invalid by Louis IX of France, some barons, led by Simon de Montfort, took up arms and, in May 1264, captured the king at the Battle of Lewes in the southeastern Downs. From then until his death at the Battle of Evesham in August 1265, Simon de Montfort largely controlled England and made important administrative and parliamentary experiments. A settlement was achieved by the Dictum of Kenilworth (1266) and finally by the Statute of Marlborough (1267), which remedied some of the baronial grievances.

island country located off the northwestern coast of mainland Europe. The United Kingdom comprises the whole of the island of Great Britain—which contains England, Wales, and Scotland —as well as the northern portion of the island of Ireland. The name Britain is sometimes used to...

October 1, 1207 Winchester, Hampshire, Eng. November 16, 1272 London king of England from 1216 to 1272. In the 24 years (1234–58) during which he had effective control of the government, he displayed such indifference to tradition that the barons finally forced him to agree to a series of...